Utterance award + requirement, and branching dialogue seeding

A dialogue line can award an achievement when reached (granted server-side,
validated against the player's current node so it can't be forged) and an
option can require an achievement to be offered (filtered out of the resolved
tree otherwise). authorGraph gains a branching form (utterance key/parent/
terminal) so option trees — not just linear lines — can be seeded. This is
gaps 1 & 2 for the Barricelli Dobby/Glitch-Hunter dialogues; phone dialing
stays stubbed.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

migrations/034_utterance_flags.sql

@@ -0,0 +1,10 @@
+-- Utterance-level flags: a dialogue line can AWARD an achievement when reached, and
+-- an option can REQUIRE an achievement to be offered (gates player choices on prior
+-- discoveries). Mirrors the merit node's award and node-enable requirements — this is
+-- how asking Dobby the name grants dobby.knows_barricelli_name, and how Glitch Hunter's
+-- "…a Norwegian-Italian mathematician" option only shows once you know it.
+
+ALTER TABLE osint.utterances ADD COLUMN awards_flag TEXT
+  CHECK (awards_flag IS NULL OR awards_flag ~ '^[a-z][a-z0-9_.-]{0,63}$');
+ALTER TABLE osint.utterances ADD COLUMN requires_flag TEXT
+  CHECK (requires_flag IS NULL OR requires_flag ~ '^[a-z][a-z0-9_.-]{0,63}$');