ci: harden trusted-bot gate bypass against human branch-updates (Closes #1031) (#1080)

The #1059 bypass keyed only on github.actor, which is dependabot[bot]
only on the bot's own push. A maintainer 'Update branch' produces a
synchronize event with github.actor=<human>, so L1/Issue/NOW gates ran
and failed on routine dependency PRs. Add a PR-author check
(github.event.pull_request.user.login) which stays dependabot[bot]
regardless of trigger. Human PRs remain fully gated.

Closes #1031

Co-authored-by: gHashTag <admin@t27.ai>

Author: gHashTag

.github/workflows/issue-gate.yml

@@ -13,7 +13,10 @@ jobs:
   check-linked-issue:
     runs-on: ubuntu-latest
     # Closes #1059: bypass Issue Gate for trusted bots (Dependabot opens dep PRs without issues)
-    if: github.actor != 'dependabot[bot]' && github.actor != 'github-actions[bot]'
+    if: >-
+      github.actor != 'dependabot[bot]' && github.actor != 'github-actions[bot]'
+      && github.event.pull_request.user.login != 'dependabot[bot]'
+      && github.event.pull_request.user.login != 'github-actions[bot]'
     steps:
       - name: Check for linked issues in PR
         env:

.github/workflows/l1-traceability.yml

@@ -9,7 +9,10 @@ jobs:
     name: Check L1 TRACEABILITY
     runs-on: ubuntu-latest
     # Closes #1059: bypass L1 gate for trusted bots (Dependabot maintains deps, not features)
-    if: github.actor != 'dependabot[bot]' && github.actor != 'github-actions[bot]'
+    if: >-
+      github.actor != 'dependabot[bot]' && github.actor != 'github-actions[bot]'
+      && github.event.pull_request.user.login != 'dependabot[bot]'
+      && github.event.pull_request.user.login != 'github-actions[bot]'
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4

.github/workflows/now-sync-gate.yml

@@ -9,7 +9,10 @@ jobs:
   check-now-freshness:
     runs-on: ubuntu-latest
     # Closes #1059: bypass NOW Sync Gate for trusted bots (deps PRs don't touch docs/NOW.md)
-    if: github.actor != 'dependabot[bot]' && github.actor != 'github-actions[bot]'
+    if: >-
+      github.actor != 'dependabot[bot]' && github.actor != 'github-actions[bot]'
+      && github.event.pull_request.user.login != 'dependabot[bot]'
+      && github.event.pull_request.user.login != 'github-actions[bot]'
     steps:
       - uses: actions/checkout@v4
         with:

docs/NOW.md

@@ -2,6 +2,12 @@
 
 Last updated: 2026-06-14
 
+## ci-bot-bypass-author-guard -- harden trusted-bot gate bypass against human branch-updates (Closes #1031)
+
+- **WHERE** (CI only): `.github/workflows/l1-traceability.yml`, `.github/workflows/issue-gate.yml`, `.github/workflows/now-sync-gate.yml`. Each gate job's `if:` guard is extended from the actor-only check (`github.actor != 'dependabot[bot]' && != 'github-actions[bot]'`) to ALSO require `github.event.pull_request.user.login != 'dependabot[bot]'` and `!= 'github-actions[bot]'`. No source, no specs, no codegen, no conformance JSON, no `gen/` artefacts touched.
+- **Why**: the original #1059 bypass keyed only on `github.actor`, which is the Dependabot bot only on its OWN push. When a maintainer clicks 'Update branch' on a Dependabot PR, the resulting `synchronize` event carries `github.actor = <human>`, so all three gates RAN and FAILED (dependency bumps legitimately have no `Closes #N` and no `docs/NOW.md` change), blocking routine dep PRs #1042/#1044/#1045/#1043/#1047/#1048/#1057/#1058 behind branch protection. `github.event.pull_request.user.login` is the PR AUTHOR and stays `dependabot[bot]` regardless of who triggered the event, so bot dependency PRs now SKIP the gates even after a human branch-update; human PRs remain fully gated by Constitutional Law L1. On `push` events `pull_request` is null so the added clause is vacuously true -- existing push behavior of now-sync-gate is unchanged. L6 untouched; L5 untouched (no silicon impact); L4 not applicable (workflow YAML, not a `.t27` spec). Closes #1031.
+- **Anchor**: phi^2 + phi^-2 = 3
+
 ## conformance-structural-to-bitexact -- promote 6 structural packs to bit-precise (IBM HFP, x87, NF4, GFTernary) (Closes #1076)
 
 - **WHERE** (conformance vectors): extends `conformance/vectors/gen_all_formats.py` with dedicated reference codecs that promote 6 packs from structural (`bitexact: false`, placeholder) to bit-precise (`bitexact: true`, `abs_error = 0` for every recorded vector): `ibm_hfp32/64/128` (IBM Hexadecimal Floating Point, base-16 exponent, layout S1:E7 excess-64:M, value = 0.M(2) * 16^(E-64)); `x87_fp80` (Intel 80-bit extended with the explicit integer bit as the MSB of the 64-bit significand field, S1:E15:SIG64, bias 16383); `nf4` (QLoRA/bitsandbytes NF4 16-entry quantile table over [-1,1], exhaustive 16-code lookup); `gfternary` (2-bit {-phi, 0, +phi}, exhaustive 4-code enumeration). Adds `make_ibm_hfp_decoder`/`ibm_hfp_encode_exact`, `make_x87_decoder`/`x87_encode_exact`, `make_nf4_decoder` + `NF4_TABLE`, `make_gfternary_decoder`, and routes them in `build_decodable`/`build_bitexact_pack`. Regenerates `INDEX_all_formats.json` (`total_packs=83, bitexact_packs=55, structural_packs=28`) and the 6 affected `*_conformance_v0.json` packs. `README.md` index, counts, SHA-256 block, and a new changelog entry updated. The catalog itself is unchanged at 83 formats; only round-trip depth increases. Follows #1070.