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---

workflows-src/modules-lifecycle.yml

@@ -1,4 +1,4 @@
-# ACDL Modules Lifecycle Pipeline — Gitea Actions (dev environment)
+# Nova Modules Lifecycle Pipeline (dev environment)
 #
 # Matrix-runs each L1 module's examples/{simple,complex}.yml contracts through
 # apply→modify→destroy against live AWS. No per-module Python. The "test" =
@@ -9,7 +9,7 @@
 # terraform files); the composition must be deterministic.
 #
 # This workflow implements pipelines/modules-lifecycle.yml (byte-identical
-# in .gitea/workflows/ and .github/workflows/).
+# in .github/workflows/).
 #
 # Lifecycle mode (REQ-134, v1.12): the `lifecycle_mode` input defaults to
 # "plan" — the lifecycle scripts run `run_platform.sh --plan-only` (fast,