Fix: FlowSpec API flat syntax broken after action dict removal

The route() function in flow/__init__.py was using ParseFlow.action dict
to look up actions for commands like 'destination', 'discard', 'interface-set'.

Commit f3587b1 removed action dicts from ParseFlowMatch/Then/Scope as part
of schema-first refactoring, but ParseFlow.action was built from those dicts,
causing KeyError when parsing flat API syntax like:
  announce flow route destination 133.130.1.219/32 discard interface-set [...]

Fix: Use schema-based action lookup via _get_route_action() method instead
of the now-empty ParseFlow.action dict.

Also removes test E from FLAKY_TESTS since the underlying bug is now fixed.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: thomas-mangin

qa/bin/functional

@@ -50,7 +50,6 @@ INTERPRETER: str = os.environ.get('INTERPRETER') or os.environ.get('__PYVENV_LAU
 # To disable retry feature entirely, comment out the _retry_flaky_tests() call in run_selected()
 FLAKY_TESTS: List[str] = [
     'D',  # api-fast: known to be flaky
-    'E',  # api-flow-merge: server occasionally times out
     'W',  # api-rr-rib: occasionally fails in batch mode
     '7',  # api-api: occasionally fails in async mode
 ]

src/exabgp/configuration/flow/__init__.py

@@ -15,7 +15,7 @@
 from exabgp.configuration.core import Parser
 from exabgp.configuration.core import Scope
 from exabgp.configuration.core import Error
-from exabgp.configuration.schema import Container
+from exabgp.configuration.schema import Container, Leaf, LeafList
 
 from exabgp.configuration.flow.route import ParseFlowRoute
 from exabgp.configuration.flow.route import ParseFlowMatch
@@ -52,9 +52,20 @@ class ParseFlow(Section):
     known.update(ParseFlowThen.known)
     known.update(ParseFlowScope.known)
 
-    action: dict[str | tuple[Any, ...], str] = dict(ParseFlowMatch.action)
-    action.update(ParseFlowThen.action)
-    action.update(ParseFlowScope.action)
+    # Route schema children for action lookup in route() function
+    _route_schema_children = {
+        **ParseFlowMatch.schema.children,
+        **ParseFlowThen.schema.children,
+        **ParseFlowScope.schema.children,
+    }
+
+    @classmethod
+    def _get_route_action(cls, command: str) -> str | None:
+        """Get action for a flow route command from schema."""
+        child = cls._route_schema_children.get(command)
+        if isinstance(child, (Leaf, LeafList)):
+            return child.action
+        return None
 
     def __init__(self, parser: Parser, scope: Scope, error: Error) -> None:
         Section.__init__(self, parser, scope, error)
@@ -84,7 +95,9 @@ def route(tokeniser: Any) -> list[Change]:
         if not command:
             break
 
-        action: str = ParseFlow.action[command]
+        action = ParseFlow._get_route_action(command)
+        if action is None:
+            raise ValueError(f'flow route: unknown command "{command}"')
 
         if action == 'nlri-add':
             handler = cast(Callable[[Any], Any], ParseFlow.known[command])