Fix ATVM watcher install-only test flow extraction

Teach generated-spec TEST FLOW parsing to honor test-install-only runtime gates, including single-quoted Cypress.env checks, and suppress plugin branches when install-only mode disables them.

Document the 2026-04-16 install-only flow mismatch so future watcher updates keep Mattermost TEST FLOW aligned with the actual generated spec path.

atvm/docs/automation/run-learnings.md

@@ -507,6 +507,15 @@ This file stores run-specific examples only when a run produced a new learning r
   - Resolve generated-spec `TEST FLOW` from the active config file's `specPattern` when the required log line is missing.
   - Treat the static template flow as a last-resort fallback only after both log-derived and config-derived `specPattern` resolution fail.
 
+## Run Learning: 2026-04-16 (Generated-spec `TEST FLOW` must honor `test-install-only` gates)
+- Observed failure mode:
+  - An install-only `cmc-e2e` run for `atvm5-ubuntu22.04` posted the full 22-step `TEST FLOW:` to Mattermost even though the generated spec for that run only executed the shorter install-only path.
+  - The watcher already used the generated spec as the source of truth, but its gate evaluator did not understand `if (Cypress.env("test-install-only") == true/false)`.
+  - That left both the install-only branch and the normal post-install branch visible to the flow extractor.
+- Action for future runs:
+  - When extracting `TEST FLOW:` from a generated spec, evaluate `test-install-only` gates the same way plugin and cutover gates are evaluated.
+  - For install-only runs, exclude the normal post-install branch and report only the actual numbered install-only steps from the generated spec.
+
 ## Run Learning: 2026-03-31 (Default vmware compute-migration options for ATVM)
 - Observed operator requirement:
   - For `cmc-migrateops-compute-migration` runs to VMware, the operator wants a stable default option set instead of having to restate the same platform flags each time.

atvm/watcher-service/atvm_run_watcher.py

@@ -1276,6 +1276,9 @@ def extract_test_flow_from_generated_spec(
                     runtime_settings[key] = match.group(1) == "true"
 
     def selected_plugin_gates() -> Optional[set[str]]:
+        install_only = runtime_settings.get("test-install-only")
+        if install_only is True:
+            return set()
         pure_plugin_type = runtime_settings.get("pure_plugin_type")
         if isinstance(pure_plugin_type, str):
             lowered = pure_plugin_type.lower()
@@ -1310,6 +1313,16 @@ def extract_test_flow_from_generated_spec(
         if normalized.startswith('if(Cypress.env("test-unaligned-fio")==true)'):
             value = runtime_settings.get("test-unaligned-fio")
             return True, value if isinstance(value, bool) else None
+        install_only_match = re.match(
+            r"""if\(Cypress\.env\((["'])test-install-only\1\)==(true|false)\)""",
+            normalized,
+        )
+        if install_only_match:
+            value = runtime_settings.get("test-install-only")
+            expected = install_only_match.group(2) == "true"
+            if isinstance(value, bool):
+                return True, value is expected
+            return True, None
         if normalized.startswith('if(Cypress.env("isRegularCutover")==false)'):
             value = runtime_settings.get("isRegularCutover")
             return True, (value is False) if isinstance(value, bool) else None