Microcompact count trigger wipes tool results every 11 calls and drives tool-call loops

## Summary

Count-based **microcompact** rewrites live tool results on a fixed cadence that has nothing to do with token pressure. On any turn with more than ~10 compactable tool calls, the agent wipes earlier observations and the model starts re-running the same commands. Hosts (AionUi / AionCore) surface this as a repeating `Microcompact: cleared 6 tool results` tip until the context is burned.

This is still the default behavior on **v0.2.11**, which is the tag currently pinned by AionCore / AionUi (`aioncoreVersion: "v0.2.1"`). I know [PR #266](https://github.com/iOfficeAI/aionrs/pull/266) later disabled legacy microcompact on `main` and replaced it with `tool_output_max_bytes`; this issue is to (1) get that change into the tag hosts actually ship, and (2) fix the remaining footguns if `microcompact_enabled` is turned back on.

## Environment

- aionrs: **v0.2.11** (AionCore git dependency)
- Host: AionUi Desktop, aionrs / Aion CLI backend
- Model: Qwen-class (observed with Qwen3.8-27B)
- Trigger: attach a large Office/PDF and ask the agent to read or summarize it

## Symptoms

- The transcript ends in an unbounded tool loop. The UI tip is almost always **exactly** `Microcompact: cleared 6 tool results`.
- Measured sessions:
- 106 tool calls, 96 results cleared, 16 microcompacts, ~2M input tokens
- 155 tool calls, 25 microcompacts, 12.1M input tokens
- other sessions: 329 / 53 and 498 / 76
- Converted files were already on disk (e.g. `api_doc.md` ~151KB). Later `ls` results were still live, but the model kept re-listing and re-converting.
- Prompt rules (“do not re-run after Microcompact, read the file instead”) did not stop it.

A 24K-token session compacted **16 times**. A 77K-token session compacted **0 times** (tools not in the compactable set). This is not a context-window overflow.

## Root cause

`crates/aion-agent/src/compact/micro.rs` (`count_trigger`):

```text
live compactable tool_result count > micro_keep_recent * 2
```

Defaults: `micro_keep_recent = 5` → fire when live results **> 10**.

Then `microcompact` keeps the 5 most recent live results and replaces older `Read` / `ExecCommand` / `Grep` / `Glob` / `Write` / `Edit` bodies with `[Tool result cleared]`. Thinking and assistant text are not touched. **Token usage and `context_window` are not consulted.**

Steady state:

```text
11 live results → clear 6 → keep 5 → grow to 11 → clear 6 again
```

That is why the tip is always **cleared 6**. Any task longer than ~10 tool steps loses its earlier observations, so the model retries.

Docs still describe this as designed (`docs/advanced.md` on the v0.2.11 line: count > 10 or a 1-hour gap).

## Config merge footgun (hosts cannot raise the default cleanly)

AionCore passes `project_dir` = conversation workspace and forwards `config.compact` through `resolve_aionui_config`. aionrs `Config::resolve` reads `/.aionrs.toml`.

When merging a project `[compact]` block, if `context_window` is still the crate default **200000** and `enabled` is not `false`, the **entire** project compact section is discarded. Hosts that write:

```toml
[compact]
micro_keep_recent = 80
```

get a no-op unless they also change `context_window` to something other than 200000 (we used `131072`).

## Suggested fix

1. **Ship PR #266** (or equivalent) in a release AionCore can pin. Hosts still run v0.2.11 with microcompact **on**.
2. If count-based microcompact remains for compatibility:
- drive it from real token pressure, not `keep_recent * 2`
- raise the default `micro_keep_recent` well above 5
- do not drop a project `[compact]` block just because `context_window` equals the crate default
3. Prefer bounding a tool result **once** when it enters history (`tool_output_max_bytes`) over rewriting earlier turns.

## Workaround used by hosts today

Write this into the session workspace **before** agent bootstrap:

```toml
[compact]
context_window = 131072
micro_keep_recent = 80
```

That changes the trigger from “> 10 live results” to “> 160” and avoids the merge discard. It is a host-side band-aid, not a substitute for fixing the trigger.

Related: [iOfficeAI/aionrs#266](https://github.com/iOfficeAI/aionrs/pull/266), [docs/advanced.md](https://github.com/iOfficeAI/aionrs/blob/main/docs/advanced.md#context-compression).

Start in crates/aion-agent/src/compact/micro.rs at count_trigger and microcompact, then inspect Config::resolve for project [compact] merging. Read docs/advanced.md and compare the behavior with PR #266; done means the shipped configuration no longer causes repeated count-based clearing or silently discards valid project settings.

Written by the indexing model from the issue text.