chore(release): prep 5.0.0 docs and version bump

[pjdoland]

Summary

Prep for the 5.0.0 release. Promotes the existing [Unreleased] CHANGELOG snapshot to [5.0.0] - 2026-05-22, expands it to cover everything merged into upstream/main after PR #287's docs refresh, bumps package.json from 4.8.0 to 5.0.0, and freshens README + admin-guide for the new surface.

Solution

CHANGELOG

• New [5.0.0] section covering the post-docs: cover post-4.8.0 changes across README, admin guide, skills, CHANGELOG #287 surface across Added / Changed / Removed / Fixed / Security / Internal.
• New Migration note (post-summary, before Added) listing the five behavior changes from 4.x that operators should review:
  • fastmcp dependency removed in favor of the official mcp SDK (fix(deps): drop fastmcp for the official mcp SDK; pin urllib3 for CVE fixes #324).
  • Shell tool and Claude UI-bridge tool paths sandboxed to jupyter_root (security: sandbox shell-tool working_directory to jupyter_root #290, security(claude): sandbox UI-bridge tool paths to jupyter_root #323).
  • Session listing no longer reads history.jsonl (fix(claude-sessions): unify session listing across NBI surfaces, drop history.jsonl gate #310).
  • Workspace file attach in Claude mode ships an @-mention pointer instead of inlined content (feat(claude): attach workspace files as @-mention in Claude mode #327).
  • Copilot WebSocket upgrades require Jupyter auth and pass an origin check (security(ws): authenticate and origin-check Copilot WebSocket upgrades #301).
• Section ordering follows Keep-a-Changelog (Added → Changed → Removed → Fixed → Security → Internal). Sub-headings under Added (Settings, Launchers, Chat sidebar and agentic UX, Copilot models, Skills and workspace config) earn their keep at this bullet density.

README

• Roadmap section flipped from 4.x to 5.x framing with a pointer to the migration note.
• New H3 in Feature highlights: Reload open files when changed on disk (feat(refresh): reload open document tabs when their files change on disk #330). TOC updated.
• Claude mode prose gains: new chat session button (feat(chat-sidebar): add "+ New Chat session" button to restart Claude #246), progress feedback for long turns (feat(chat-sidebar): real progress feedback during long Claude tasks #254), @-mention behavior change (feat(claude): attach workspace files as @-mention in Claude mode #327).
• Other coding-agent launcher tiles subsection notes the start-directory picker (Allow user choose dir from tile #332).
• Plugins section freshened with the marketplace picker (Add plugin marketplace picker #284) and Update button (feat(plugins): show marketplace details and add an Update button #303).
• Claude MCP section freshened with per-workspace toggle (feat(claude-mcp): disable MCP servers per workspace #286) and JSON-paste path (feat(mcp): JSON-paste path in Add MCP server dialog #285).

docs/admin-guide.md

• pip install example block swapped from fastmcp==2.x.* to mcp==1.27.* and notebook-intelligence==5.0.*, with a cross-reference to the changelog migration note.
• Version matrix gains a 5.0.x row.
• New callout in the env-var/traitlet section noting that some NBI settings live in JupyterLab's Settings Editor rather than the NBI Settings dialog. Names refresh_open_files_on_disk_change as the notable case and the overrides.json path for org-wide overrides.

package.json

• Version bumped from 4.8.0 to 5.0.0. The Python _version.py is auto-generated by Hatchling from this value on build, so no separate Python version bump is needed.

Testing

Documentation and version-bump PR; no executable change.

• python3 -c "import json; json.load(open('package.json'))" — package.json is valid JSON.
• Visual check: CHANGELOG renders cleanly, all links resolve, no broken bullets.
• Em-dash grep on added lines returned 0 hits (project convention).

Two rounds of six persona reviewers (changelog fidelity, backward-compat / semver, admin-guide cross-reference, security-claim audit, README freshness, style + Keep-a-Changelog conformance) shaped the final wording:

• Round 1 surfaced overclaims on three Security entries (security: enforce 0o600 on the encrypted GitHub token file #293, security(mcp): validate user MCP config shape before persisting #299, security(claude): sandbox UI-bridge tool paths to jupyter_root #323), a Add plugin marketplace picker #284 vs feat(plugins): show marketplace details and add an Update button #303 mis-attribution, the absent migration note, 3 em dashes, and a stale fastmcp==2.x.* pin recommendation in the admin guide.
• Round 2 surfaced the missing security(ws): authenticate and origin-check Copilot WebSocket upgrades #301 migration bullet, the missing 5.0.x row in the version matrix, the missing README TOC entry, and two structural nits (an overpromised sub-heading and an orphan bullet).

All fix-before-ship findings applied.

Risks / follow-ups

• Cipher description in security: enforce 0o600 on the encrypted GitHub token file #293's CHANGELOG entry says "AES-GCM-encrypted Copilot token". The underlying cipher is Fernet (AES-128-CBC + HMAC). Out of scope for this docs PR; worth a follow-up correction since it's a minor factual nit on a security entry.
• Admin guide HTTP kill-switch row in the Failure modes table is not added; the kill switch is documented in the dedicated subsection. Worth a future tightening.
• README first-run tour mention in Quick start was deferred; the tour is discoverable in the UI on first open.
• Terminal drag-drop trust-model note (docs/admin-guide.md:549) is mildly imprecise post-feat(claude): attach workspace files as @-mention in Claude mode #327 (the @-mention path bypasses the staging dir for workspace files). Worth a future tweak.

Issue linkage

No single issue — this is the 5.0.0 release prep PR. Closes the post-4.8.0 doc lag.

[mbektas]

@pjdoland can you resolve the conflicts

[pjdoland]

Resolved. Also added doc updates relating to #339