[codex] Refresh docs and agent skills (#4693)

## Thinking Path

> - Paperclip orchestrates AI agents through a company-scoped control
plane
> - Contributors and agents need docs and skills that match the current
V1 behavior
> - The source branch included documentation updates alongside
implementation work
> - Keeping docs and skill guidance separate makes the implementation PR
easier to review
> - This pull request refreshes the V1 docs and agent-operating guidance
without changing runtime behavior
> - The benefit is current contributor guidance that can merge
independently from code changes

## What Changed

- Refreshed V1 product, goal, implementation, database, and development
documentation.
- Updated the Paperclip heartbeat skill guidance and create-agent skill
references.
- Added the Paperclip plan-to-task conversion skill.
- Updated release changelog skill guidance.

## Verification

- `git diff --check public-gh/master..HEAD` passed in the PR worktree
after the Greptile fix.
- Greptile Review passed on head `673317ed` with zero unresolved review
threads.
- GitHub PR checks passed on head `673317ed`: `policy`, `verify`, `e2e`,
and `security/snyk (cryppadotta)`.

## Risks

- Low runtime risk because this branch only changes docs and skill
guidance.
- Documentation may need follow-up wording adjustments if reviewers want
a different framing for V1 behavior.

> For core feature work, check [`ROADMAP.md`](ROADMAP.md) first and
discuss it in `#dev` before opening the PR. Feature PRs that overlap
with planned core work may need to be redirected — check the roadmap
first. See `CONTRIBUTING.md`.

## Model Used

- OpenAI Codex, GPT-5 coding agent, tool-enabled terminal/GitHub
workflow. Exact runtime context window was not exposed by the harness.

## Checklist

- [x] I have included a thinking path that traces from project context
to this change
- [x] I have specified the model used (with version and capability
details)
- [x] I have checked ROADMAP.md and confirmed this PR does not duplicate
planned core work
- [x] I have run tests locally and they pass
- [x] I have added or updated tests where applicable
- [x] If this change affects the UI, I have included before/after
screenshots
- [x] I have updated relevant documentation to reflect my changes
- [x] I have considered and documented any risks above
- [x] I will address all Greptile and reviewer comments before
requesting merge

---------

Co-authored-by: Paperclip <noreply@paperclip.ing>

skills/paperclip-create-agent/references/api-reference.md

@@ -42,8 +42,13 @@ Request body matches agent create shape:
   "adapterType": "claude_local",
   "adapterConfig": {
     "cwd": "/absolute/path",
-    "model": "claude-sonnet-4-5-20250929",
-    "promptTemplate": "You are CTO..."
+    "model": "claude-sonnet-4-5-20250929"
+  },
+  "instructionsBundle": {
+    "entryFile": "AGENTS.md",
+    "files": {
+      "AGENTS.md": "You are CTO..."
+    }
   },
   "runtimeConfig": {
     "heartbeat": {