feat(okf): one bundle-id rule, reconciled against the mount and origin-marked

[skip-docs] — the invariant row for this plan lands in Step 13, where the mutations
that force it have been measured. Documenting a seam before its measurement is
the claim-without-evidence class this repo writes rows against.

Co-Authored-By: Claude <claude-opus-5>

src/portfolio_optimiser/mandate.py

@@ -51,8 +51,9 @@ class Approach(BaseModel):
     id: str = Field(min_length=1)
     label: str = Field(min_length=1)
     description: str = ""
-    #: Which knowledge base this approach belongs to (§ C.7), by the base's id — the directory's
-    #: BASENAME, exactly as ``explore._bundle_index`` names it. DEFAULTS to empty, meaning "no base
+    #: Which knowledge base this approach belongs to (§ C.7), by the base's id — exactly as
+    #: ``okf.reconcile_bundle_id`` resolves it (the base's own declaration where it makes one, the
+    #: mount's basename otherwise). DEFAULTS to empty, meaning "no base
     #: named": a legitimate statement when the run has only one base to name, and what keeps every
     #: mandate written before multi-base existed valid and dispatchable unchanged.
     #: