feat(agent): confine agent file/shell tools to a selectable workspace (#3665)

* feat(agent): workspace confinement via context-local binding + get_workspace tool

Bind the per-turn workspace once in execute_tool_block; the shared path
resolvers (_resolve_tool_path / _resolve_search_root) and the subprocess cwd
helper (agent_cwd) read it, so file tools + bash/python are confined centrally
and a new tool that uses the shared helpers cannot accidentally bypass it.

Adds the admin-gated /api/workspace/browse picker, a workspace pill + directory
modal (reusing existing modal/button CSS), the /workspace slash command, and a
get_workspace tool (replaces a system-prompt block). Confinement is OS-agnostic
(realpath/normcase/commonpath) and docker-safe (container paths, no host
assumptions). Reopens #2023.

* ux(workspace): clarify workspace is not a sandbox

Picker modal note + pill tooltip + get_workspace tool/output wording now state
plainly: read_file/write_file/edit_file/grep/glob/ls are confined to the folder,
but bash/python only start there (cwd) and are not sandboxed. Modal note reuses
the existing .muted class.

* fix(agent): treat an active workspace as file-work intent

A vague low-signal message (e.g. "look at the local project") matches no
domain keywords, so tool retrieval is skipped and only always-available tools
are offered — leaving the agent with no file access even though a workspace is
set. When a workspace is active, include the file/code tools (incl.
get_workspace) on low-signal turns so the agent can act on the folder.

Also requires the tool index (ChromaDB) to be reachable for normal retrieval;
that is an environment dependency, not part of this change.

* ux(workspace): hide pill + overflow entry in chat mode

Workspace only scopes the agent's file/shell tools, so the pill and the
overflow 'Workspace' entry are agent-only now — hidden in chat mode like the
bash toggle. Mode read from the DOM in syncWorkspaceIndicator; applyMode() is
called from the agent/chat setMode handler.

* prompt(tools): steer bash/python to defer to the dedicated file tools

bash/python schema descriptions (what native-tool-calling models read) were
bare and gave no steer, so models would do file ops via the shell (e.g. writing
SVG/HTML, which then dumps raw markup into the tool preview). Tell bash/python
in the schema + tool-index + prompt section to prefer read_file/write_file/
edit_file/grep/glob/ls and only be used for what those do not cover.

* prompt(tools): keep bash/python deferral generic (no hardcoded tool names)

Reference 'a dedicated tool' rather than listing read_file/write_file/grep/etc.
by name, so the guidance does not go stale if those tools are renamed.

* style(workspace): drop em-dashes from added code comments/strings

* ux(workspace): terser non-sandbox note in picker (no tool-name list)

* ux(workspace): mirror terse non-sandbox wording in pill tooltip

* chore: untrack local venv symlink (run-only, not part of the feature)

* prompt(workspace): keep get_workspace text generic (no hardcoded tool names)

* fix(agent): low-signal + workspace surfaces only read-only file tools

Intersect the files tool group with PLAN_MODE_READONLY_TOOLS so a vague message
in a workspace exposes read_file/grep/glob/ls/get_workspace for exploration, but
not write_file/edit_file/bash/python -- those wait for a request that actually
calls for them (RAG retrieval still adds them on a real ask).

* feat(workspace): cap browse listing at 500 dirs with a truncated hint

Mirror the filesystem_tools._CODENAV_MAX_HITS pattern with a module-local
_MAX_BROWSE_DIRS so a directory with thousands of children does not dump every
row into the picker; the response carries a truncated flag and the modal tells
the user to type a path to jump in.

* chore: untrack local venv symlink (run-only artifact)

* fix(workspace): vet the workspace root against the sensitive-path deny list at bind time

The in-workspace resolver deny-lists sensitive paths inside the workspace,
but the empty-path search root is the workspace itself, so a workspace of
~/.ssh could be listed via ls with no path. vet_workspace() (public, in
tool_execution next to the resolvers) rejects non-directories and sensitive
roots before the path is ever bound; chat_routes uses it instead of its
inline isdir check.

* fix(workspace): reject filesystem roots and stop showing rejected workspaces as active

Review findings from #3665:

P2: vet_workspace accepted / (and would accept drive/UNC roots), which makes
every absolute path 'inside' the workspace and collapses confinement into
host-wide file access. A root is its own dirname, so reject when
dirname(resolved) == resolved; the browse response now carries a selectable
flag and the picker disables 'Use this folder' on unselectable dirs.

P3: /workspace set stored any string client-side and the chat route silently
dropped rejected values, so the pill could claim a confinement that was not
in effect. New admin-gated /api/workspace/vet validates manual paths before
they persist (canonical path returned), and when a posted workspace is
rejected at send time the stream emits workspace_rejected so the client
clears the stored value and toasts instead of continuing silently.

* fix(workspace): check caller privilege before vetting the posted workspace

Review finding: /api/chat_stream called vet_workspace() on the posted value
for every caller and emitted workspace_rejected on failure, so a non-admin
who can chat but cannot use file/shell tools could distinguish existing
directories from missing/file/sensitive/root paths by whether the event
appeared. The resolution now lives in _resolve_request_workspace, which
drops the submitted value uniformly for non-admin callers, with no vetting
and no event, before the path ever touches the filesystem. Admin and
single-user behavior is unchanged. Test pins that valid and invalid paths
are indistinguishable for a non-admin and that vet_workspace is never
invoked for them.

src/tool_index.py

@@ -67,14 +67,15 @@ COLLECTION_NAME = "odysseus_tool_index"
 # Each tool gets a searchable description that helps retrieval.
 # These are richer than the system prompt one-liners — they're for embedding.
 BUILTIN_TOOL_DESCRIPTIONS: Dict[str, str] = {
-    "bash": "Run shell commands on the server. Install packages, check files, git operations, system info, and process management. Do not use for web lookup/search; use web_search or web_fetch when web tools are available.",
-    "python": "Execute Python code for computation, data processing, math, scripting, and parsing. Not for writing code for the user. Do not use for web lookup/search; use web_search or web_fetch when web tools are available.",
+    "bash": "Run shell commands on the server. Install packages, git operations, builds, system info, process management. Prefer a dedicated tool whenever one fits the job (file read/write/edit, search, listing); use bash only for what no dedicated tool covers. Do not use for web lookup/search; use web_search or web_fetch when web tools are available.",
+    "python": "Execute Python code for computation, data processing, math, scripting, and parsing. Not for writing code for the user. Prefer a dedicated tool for reading, writing, or searching files; use python only for what no dedicated tool covers. Do not use for web lookup/search; use web_search or web_fetch when web tools are available.",
     "web_search": "Quick single web lookup for a fact, current event, latest/current information, or doc mid-task. Use this instead of bash/curl/python/requests for web searches. NOT for 'research X' / 'do research on X' requests — those are deep-research jobs (use trigger_research). web_search = one query; trigger_research = a full researched report in the sidebar.",
     "web_fetch": "Fetch and read the text content of a specific URL/website the user names (e.g. 'check example.com', 'open this link'). Use when you have a concrete URL; for open-ended lookups use web_search instead.",
     "read_file": "Read a file from disk and return its contents. View source code, config files, logs. Supports an optional line range (offset/limit) for large files.",
     "grep": "Search file CONTENTS for a regex across a directory tree (ripgrep-backed, honours .gitignore). Returns file:line:match. Use to find where code/symbols/strings live — prefer over bash grep.",
     "glob": "Find FILES by glob pattern (e.g. '**/*.py'), newest first. Use to locate files by name/extension — prefer over bash find/ls.",
     "ls": "List a directory's entries (folders then files with sizes). Use to see what's in a folder — prefer over bash ls.",
+    "get_workspace": "Return the absolute path of the active workspace folder the user is working in. File tools are confined to it; the shell starts there but is not sandboxed. Call this first when the user refers to 'the project'/'the code'/'this folder' without giving a path, instead of asking them.",
     "write_file": "Write/create or fully rewrite a file ON DISK (source code, configs, project files). Use for new files or full rewrites — NOT create_document (editor panel) and NOT a bash heredoc.",
     "edit_file": "Edit an existing file ON DISK by exact string replacement (fix a bug, change a function). Shows a diff. The tool for changing files on disk — NOT edit_document (editor panel) and NOT bash sed/heredoc.",
     "create_document": "Create a new document in the editor panel. For code, articles, text content longer than 15 lines, unless an already-open document/email draft is the obvious target. If an email compose draft is open, edit that draft instead of creating another document.",