feat(P1): remove gitea/gitlab from synced files + simplify docs (REQ-230,231,232)

Genericize forge-detection code: gitea→forge/generic_forge, GITEA_ACTOR→FORGE_ACTOR.
Drop .gitea byte-identity test assertions (keep GitHub-side + contract conformance).
Add test_no_forge_mentions.py guard test (REQ-230).
Delete completed migration docs (NOVA_MIGRATION.md, NOVA_AWS_MIGRATION.md).
Move NO_HUMANS_THESIS.md to .ciagent/ (internal artifact).
Strip ciagent-internal provenance from synced docs (REQ-/D-/P-/CAP- IDs,
milestone headers, .ciagent/PROJECT.md citations).
Trim README.md (reusable deploy section, local key rotation paragraph).
Fix version-tag drift (@v1.13→@v1.19, acdl/→nova/).

---ci---
project: acdl
phase: 1
milestone: v1.20
status: execute
requirements: [REQ-230, REQ-231, REQ-232]
---/ci---

.github/workflows/deploy.yml

@@ -1,4 +1,4 @@
-# ACDL Reusable Deploy Workflow — Gitea Actions (dev environment)
+# Nova Reusable Deploy Workflow (dev environment)
 #
 # This reusable workflow implements the central deployment pipeline contract:
 #   pipelines/contract.yml (validated against schemas/deploy-pipeline.schema.json)
@@ -8,7 +8,7 @@
 # declared difference is the forge/runtime, not the stages or commands.
 #
 # Consumer repos invoke this workflow via a versioned tag (floating MAJOR + MINOR):
-#   uses: acdl/.gitea/workflows/deploy.yml@v1.9   (Gitea)
+#   uses: nova/.github/workflows/deploy.yml@v1.19
 #   uses: acdl/.github/workflows/deploy.yml@v1.9  (GitHub)
 #
 # Unversioned references (@main, bare) are discouraged — the consumer's setup
@@ -38,8 +38,8 @@
 #   that matches repo:org/consumer-repo:ref:refs/heads/main, and the session
 #   policy restricts view/update to resources tagged acdl:owner=<consumer-repo>.
 #
-#   Override (where OIDC is unavailable, e.g. Gitea pending
-#   go-gitea/gitea#36988): set NOVA_AWS_ACCESS_KEY_ID + NOVA_AWS_SECRET_ACCESS_KEY
+#   Override (where OIDC is unavailable, e.g. pending
+#   upstream forge OIDC support): set NOVA_AWS_ACCESS_KEY_ID + NOVA_AWS_SECRET_ACCESS_KEY
 #   as repository secrets. The platform-managed scheduled pipeline rotates
 #   the key on a daily cadence. When .env.secrets is used locally instead,
 #   rotating the key out of band is the consumer's responsibility.