Pin tpt prompt provenance to immutable refs

Replace mutable branch pointers with the exact source commit and
historical base-to-commit range. Normalize the substantive scope
while leaving the recorded raw response unchanged.

Prompt-IO: ai/prompt-io/claude/20260813T001102Z_27c34aeb_prompt_io.md

(this patch was generated in some part by `opencode` using `gpt-5.6-sol` (`openai`))

ai/prompt-io/claude/20260813T001102Z_27c34aeb_prompt_io.md

@@ -3,8 +3,8 @@ model: claude-opus-5
 service: claude
 session: 7b9c97c4-fff7-4ac4-97fb-35720453308e
 timestamp: 2026-08-13T00:11:02Z
-git_ref: 27c34aeb
-scope: docs+code
+git_ref: 27c34aebb615c30d4039fa399f4ce2766ed7ba2c
+scope: code
 substantive: true
 raw_file: 20260813T001102Z_27c34aeb_prompt_io.raw.md
 ---

ai/prompt-io/claude/20260813T001102Z_27c34aeb_prompt_io.raw.md

@@ -2,15 +2,15 @@
 model: claude-opus-5
 service: claude
 timestamp: 2026-08-13T00:11:02Z
-git_ref: 27c34aeb
-diff_cmd: git diff main..ng_tpts_planning
+git_ref: 27c34aebb615c30d4039fa399f4ce2766ed7ba2c
+diff_cmd: git diff 3ad7e7e5dc28aa336499725a03744fc10c6c0026..27c34aebb615c30d4039fa399f4ce2766ed7ba2c
 ---
 
 # Raw output — next-gen tpt-backend implementation plans
 
 ## Generated planning docs
 
-> `git diff main..ng_tpts_planning -- ai/tpt-backends/`
+> `git diff 3ad7e7e5dc28aa336499725a03744fc10c6c0026..27c34aebb615c30d4039fa399f4ce2766ed7ba2c -- ai/tpt-backends/`
 
 Five markdown docs. `00_shared_backend_contract.md` is normative
 and the other three are written against it so they can be worked
@@ -43,7 +43,7 @@ independently:
 
 ## Generated example code
 
-> `git diff main..ng_tpts_planning -- examples/multihost/wg_lan/`
+> `git diff 3ad7e7e5dc28aa336499725a03744fc10c6c0026..27c34aebb615c30d4039fa399f4ce2766ed7ba2c -- examples/multihost/wg_lan/`
 
 - `wg_maddr.py` — `WGTunnelledAddr(msgspec.Struct, frozen=True)`
   carrying `bearer: tuple[str, int]`, `peer_pubkey: str`,