Builds on the zero-match feedback fix (previous commit) to close the silent-hang
symptom: when memory is at capacity, a failed `add`/`replace`/`remove`
consolidation could loop the whole turn to iteration-budget exhaustion and
deliver no user-facing reply.
#41755 turned the at-capacity overflow error into a *commanded* in-turn retry
("...then retry this add — all in this turn"); combined with the fragile
substring-only `replace`/`remove` matching (LLMs can't reliably re-quote a long
entry verbatim), the model loops add↔replace on inexact guesses until the turn
dies. The existing tool_guardrails halt would catch this, but hard_stop_enabled
is opt-in (off by default), so a default install still hangs.
This fixes it at the memory layer without changing global guardrail behavior:
- MemoryStore tracks per-turn consolidation failures; after a cap (3) it drops
the "retry in this turn" instruction and returns a terminal "leave memory
unchanged, continue your reply" result, so a failed memory side effect can
never block the turn's reply.
- The counter resets on any successful write (progress) and at each turn
boundary (turn_context.reset_consolidation_failures, guarded via getattr so
plugin memory stores without the method are a no-op).
Co-authored-by: liuhao1024 <sunsky.lau@gmail.com>