fix: Telegram subject code-wrap, migration backup path cleanup

[chrisli30]

• refactor: derive migration backup path from db_path, drop dead BackupConfig

backup_dir was only consumed by the migration-time backup. The nested
BackupConfig (Enabled/IntervalMinutes/BackupDir) was never read — periodic
backups are not wired up anywhere. Remove the YAML field, the
/tmp/ap-avs-backup default, and the dead struct. The migrator now writes
to <db_path>_backup automatically, keeping backups co-located with the DB
instead of falling back to /tmp.

• fix: wrap Telegram subject prefix inside block

The Simulation:/Run #N:/Run Node: prefix now renders inside the code
block alongside the workflow name, restoring the pre-rename behavior
where the whole "Simulation: WorkflowName" chunk was code-wrapped.

[claude]

Code Review

Overview

This PR contains two independent fixes:

1. Telegram formatting: Wraps the subject prefix (Simulation:, Run #N:, Run Node:) inside the <code> block alongside the workflow name, fixing the pre-rename rendering behavior.
2. Config cleanup: Removes the never-implemented BackupConfig struct and derives the migration backup path from db_path instead of a separate config field.

Both changes are well-scoped and easy to follow.

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Telegram Subject Code-Wrap (summarizer_format_telegram.go)

Looks correct. Moving sb.WriteString("<code>") before the prefix if block is the minimal, correct fix. The updated comment on formatSubjectWithBoldName accurately describes the new behavior.

The test suite in summarizer_format_test.go is thorough — all affected cases are updated and the unchanged "no prefix" case is implicitly verified by not appearing in the diff.

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Migration Backup Path Cleanup (core/config/config.go)

One documentation inconsistency to fix:

The comment added to aggregator.example.yaml:

# Migration backups are written to <db_path>-backup automatically.

uses a hyphen (-backup), but the actual code in config.go uses an underscore:

BackupDir: configRaw.DbPath + "_backup",

These don't match. The comment should read <db_path>_backup to avoid operator confusion.

Removal of BackupConfig is correct. Looking at aggregator.go:253 and backup/backup.go, StartPeriodicBackup is never called from the aggregator startup path — the service is created (backup.NewService) but only used by the migrator for point-in-time migration backups, not periodic ones. Removing BackupConfig.Enabled and BackupConfig.IntervalMinutes doesn't change runtime behavior.

BackupDir on Config is still live — it's passed to backup.NewService at aggregator.go:253, which uses it for migration-time backups. Good that the field was retained; the PR correctly keeps it while changing how the value is derived.

Potential edge case: If DbPath is empty (misconfigured aggregator), BackupDir becomes the bare string "_backup", a relative path. The old /tmp/ap-avs-backup default was an absolute path. This is minor since an empty DbPath would cause the DB itself to fail to open, but it's worth noting.

Breaking YAML change: Removing backup_dir from ConfigRaw means existing aggregator.yaml files with a backup_dir key will silently ignore it. Since the field was effectively dead (its value only reached /tmp/ap-avs-backup by default and periodic backups were never wired up), this is an acceptable cleanup — but consider a log warning on startup if the key is still present in the YAML, or at minimum mention it in the PR/changelog for operators.

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Summary

#	Severity	Location	Issue
1	Minor bug	config/aggregator.example.yaml	Comment says <db_path>-backup but code produces <db_path>_backup (hyphen vs underscore)
2	Nit	core/config/config.go	Empty DbPath produces relative _backup path; old default was absolute /tmp/ap-avs-backup
3	Info	Deployment	backup_dir YAML removal is a silent breaking change for any operator config that had it set

The Telegram fix and dead-code removal are clean. Fix the comment inconsistency (issue #1) before merging.

[Copilot]

Pull request overview

This PR updates Telegram notification formatting to code-wrap the full subject prefix + workflow name, and simplifies migration-time database backup configuration by deriving the backup directory from db_path and removing unused backup config fields.

Changes:

• Wrap Telegram subject prefix + workflow name together inside a single <code> block for consistent rendering.
• Remove unused BackupConfig/YAML fields and derive migration backup path directly from db_path.
• Update/align tests and config examples with the new formatting and backup behavior.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

File	Description
core/taskengine/summarizer_format_test.go	Updates expected Telegram output strings to match the new <code> wrapping behavior.
core/taskengine/summarizer_format_telegram.go	Changes subject formatting to wrap prefix + workflow name within <code>.
core/config/config.go	Removes dead backup config structs/fields and derives BackupDir from DbPath.
config/aggregator.example.yaml	Removes backup_dir and documents the new derived backup directory behavior.

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