Bump structlog>=26.1.0 and croniter>=6.2.2 to fix memory leaks

[jason810496]

• related issue: Small memory leak from the dag-processor in Airflow 3.x #50708
• related comment: Small memory leak from the dag-processor in Airflow 3.x #50708 (comment)
• upstream fixes: Use WeakKeyDictionary for WRITE_LOCKS to prevent file object leaks hynek/structlog#807 (released in structlog 26.1.0), Fix memory leak by removing TIMESTAMP_TO_DT_CACHE pallets-eco/croniter#185 (released in croniter 6.1.0, fully effective from 6.2.0; leap-year get_prev fix in 6.2.1)

Why

The dag-processor memory leak in #50708 has two library-level root causes that are already fixed upstream: structlog leaks one lock and file-handle entry in WRITE_LOCKS per Dag-file log reopen on every parse cycle (fixed in 26.1.0), and croniter leaks on every cron schedule evaluation. The current minimums (structlog>=25.4.0, croniter>=2.0.2) still admit the leaky versions, so constraint-less installs and release-branch constraints can resolve them. Every released Airflow to date ships a leaky structlog (3.2.2 constraints pin 25.5.0).

The croniter floor is 6.2.2 rather than 6.1.0: the 6.1.0 wheel still ships the EXPRESSIONS global cache (removed in 6.2.0 despite the 6.1.0 changelog claim), and 6.2.1 fixed get_prev skipping Feb 29 on leap years, which feeds CronMixin._get_prev via infer_manual_data_interval and _align_to_prev. constraints-3.2.2 and constraints-3.3.0 already pin croniter==6.2.2.

Verified empirically: on 3.2.2-era versions with example Dags only, the standalone stack leaks ~34 MB/h of anonymous memory concentrated in the dag-processor, while a main-based image already running structlog 26.1.0 and croniter 6.2.x is near-flat (~9 MB/h residual across 8 processes). constraints-main already resolves the fixed versions, so this bump changes nothing for main CI and only raises the floor.

What

• Bump structlog>=25.4.0 to structlog>=26.1.0 in all 8 declaring distributions: airflow-core, task-sdk, airflow-ctl, and shared dagnode, listeners, logging, observability, providers_discovery.
• Bump croniter>=2.0.2 to croniter>=6.2.2 in airflow-core.
• Remove workarounds in shared/logging that are dead code at the new structlog floor: the WRITE_LOCKS WeakKeyDictionary monkeypatch in configure_logging (structlog 26.1.0 ships it natively) and the _BYTES_LOGGER_HAS_NAME fallback in NamedBytesLogger (BytesLogger always has the name slot now). The _WRITE_LOGGER_HAS_NAME detection stays, since WriteLogger has not received the upstream name slot yet.
• Regenerate uv.lock (requirement metadata only, locked versions unchanged: structlog 26.1.0, croniter 6.2.4).

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Was generative AI tooling used to co-author this PR?

• Yes, with help of Claude Code Fable 5 following the guidelines

[github-actions]

Backport successfully created: v3-3-test

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Status	Branch	Result
✅	v3-3-test