Make AGENTS.md paths repo-relative so a drive move stops rotting it

Every path in Important Paths, Useful Commands, and External Context named the
lost E: drive. CLAUDE.md is a bare @AGENTS.md import, so those dead paths were
loaded into every session in this repo.

Swapping E: for F: would only reset the timer, so the paths are now
repo-relative and gamecult-ops is named as a sibling repo rather than an
absolute location. All ten referenced files were confirmed present after the
move; none were lost with the drive.

The interpreter guidance was worse than stale. It pointed at a venv under the
dead drive, and the documented fallback did not work either: this workstation
had no Python at all, and both `python` and `python3` resolved to Microsoft
Store aliases that print an install prompt and exit 0. Python 3.13.15 is now
installed to the user scope and ahead of WindowsApps on PATH, both tools were
run under it, and the section documents that failure mode so the next agent
installs an interpreter instead of hard-coding a path to someone else's.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

AGENTS.md

@@ -41,31 +41,24 @@ The planned non-shared-by-default layer is:
 
 ## Important Paths
 
-- Project root: `E:\Projects\Heimdall`
-- Shared architecture: `E:\Projects\Heimdall\docs\architecture.md`
-- Implementation plan: `E:\Projects\Heimdall\docs\implementation-plan.md`
-- Repixelizer profile: `E:\Projects\Heimdall\docs\app-profiles\repixelizer.md`
-- StreamPixels profile: `E:\Projects\Heimdall\docs\app-profiles\streampixels.md`
-- Spotiverse profile: `E:\Projects\Heimdall\docs\app-profiles\spotiverse.md`
-- Handoff summary: `E:\Projects\Heimdall\notes\fresh-workspace-handoff.md`
-- State CLI: `E:\Projects\Heimdall\tools\heimdall_state.py`
-- Pre-compaction helper: `E:\Projects\Heimdall\tools\heimdall_prepare_compaction.py`
+Paths are relative to the repository root. Do not hard-code an absolute drive
+path into this file; the repo has already been moved between drives once, and
+every absolute path in here rotted the moment it happened.
+
+- Shared architecture: `docs/architecture.md`
+- Implementation plan: `docs/implementation-plan.md`
+- Repixelizer profile: `docs/app-profiles/repixelizer.md`
+- StreamPixels profile: `docs/app-profiles/streampixels.md`
+- Spotiverse profile: `docs/app-profiles/spotiverse.md`
+- Handoff summary: `notes/fresh-workspace-handoff.md`
+- State CLI: `tools/heimdall_state.py`
+- Pre-compaction helper: `tools/heimdall_prepare_compaction.py`
 
 ## Useful Commands
 
-This repo does not carry a dedicated virtualenv yet. Use any working Python
-3.11+ interpreter. On this workstation,
-`E:\Projects\repixelizer\.venv\Scripts\python.exe` is known-good.
-
-Preferred here:
-
-```powershell
-E:\Projects\repixelizer\.venv\Scripts\python.exe .\tools\heimdall_state.py status
-E:\Projects\repixelizer\.venv\Scripts\python.exe .\tools\heimdall_state.py add-evidence --type design --status accepted --note "..."
-E:\Projects\repixelizer\.venv\Scripts\python.exe .\tools\heimdall_prepare_compaction.py
-```
-
-Fallback if a normal `python` command exists:
+Both state tools are single-file, standard-library-only Python. They need no
+virtualenv and no installed dependencies. Run them with `python` from the repo
+root:
 
 ```powershell
 python .\tools\heimdall_state.py status
@@ -73,6 +66,19 @@ python .\tools\heimdall_state.py add-evidence --type design --status accepted --
 python .\tools\heimdall_prepare_compaction.py
 ```
 
+Verified 2026-09-06 against Python 3.13.15 installed to the user scope; `py -3`
+resolves the same interpreter.
+
+If `python --version` prints an install prompt rather than a version, PATH is
+resolving the Microsoft Store alias in `WindowsApps` instead of a real
+interpreter, and it will still exit 0 while doing so. Install a real Python and
+put it ahead of `WindowsApps` on PATH rather than hunting for some other
+interpreter to hard-code here:
+
+```powershell
+winget install --id Python.Python.3.13 --scope user
+```
+
 ## Session Bootstrap And Re-entry Protocol
 
 On fresh session load:
@@ -134,5 +140,5 @@ user did not say so yet:
 
 - For StreamPixels architecture/auth context, prefer the indexed `StreamPixels`
   repo through `voidbot` before filesystem spelunking.
-- For GameCult deployment and host conventions, check
-  `E:\Projects\gamecult-ops` before improvising infra claims.
+- For GameCult deployment and host conventions, check the sibling `gamecult-ops`
+  repo in the same projects root as this one before improvising infra claims.