feat(temporal): resolve unregistered activities by func-name convention

[avfirsov]

What

Adds a convention fallback to Temporal dispatch resolution: when a dispatch name doesn't resolve to a registered activity/workflow, fall back to an exported Go function/method of that name following the activity/workflow naming convention (suffix Activity / Workflow).

Resolves the dispatch at the inferred tier (graph.OriginASTInferred, confidence 0.6, temporal_resolution_via="convention") — it's a naming convention, not a register-confirmed binding. Tries the dispatch name directly, then its const-deref value.

Why

Activity repos commonly hold the functions but register them from a separate worker-runner, so the register-based index never sees them and the dispatch stays broken_dispatch. This recovers the common 1:1 func name == dispatch string case (Pattern 2: ActivityFuncName const → the function).

How it fits current main

Ported onto the post-#82 resolver:

• lookupConvention(kind, name, callerRepo, callerLang) mirrors idx.lookup's same-language gate (a Go dispatch never lands on a like-named symbol in another language).
• The fallback block runs after const-deref and before the cross-language join — a same-language convention match is a stronger signal than a speculative cross-language by-string match.
• A bounded funcByName index (convention-named Go funcs/methods only) is built in buildTemporalIndex.

Includes a small prerequisite fix to goConstLiteralValue: it now selects the matching const_spec by name inside a grouped const ( … ) block (previously only single-spec blocks yielded a const value), which the feature's own grouped-const dispatch test exercises.

Tests

New e2e TestTemporalE2E_GoUnregisteredActivityByConvention (workflow dispatches via an ActivityFuncName const to an unregistered GetProductOfferingActivity). go build ./... clean; resolver / parser / indexer suites pass.