Changelog: add 49 buffered entries for 3.9

[erikdarlingdata]

Summary

This adds 49 entries to the Unreleased section of CHANGELOG.md, each with its link. They cover the PRs merged to dev since the last splice (#4080). Only CHANGELOG.md changes.

• 41 entries come from the changelog buffer.
• 8 come from the ## CHANGELOG entry section of client-site PR bodies: Log readers: a forged number can't blind plan capture, and the binary route skips escape+regex on a tail that can't match (#4058) #4089, Install scripts: the service account gets Read & Execute on the install root and Modify only where it writes (#4052) #4090, Store Checkpointer Pressure judges the average sync per checkpoint, not the interval's sum (#4037) #4096, get_resource_semaphore: add interval_seconds beside sample_interval_seconds (#3653 item 17) #4103, Decode pg_read_binary_file log tail in the connected database's server_encoding (#4062) #4106, MCP tool schemas exclude DI services by type, closing a reflection race that leaked them into tools/list (issue-4075) #4110, Fix #4130: fire-and-track the daily retention purge off the launch loop #4133 and 4053 part b2: pg_plan_capture reads csvlog when it's on (self-hosted) #4137. I checked the first seven's main facts against each diff and rewrote them in the house format. The PR tender added 4053 part b2: pg_plan_capture reads csvlog when it's on (self-hosted) #4137 afterward, checked against that PR's own account of its change.

Checks on the entries

Three checkers read each buffered entry against its merged diff. They fixed these:

• get_alert_history/set_mute_rule_enabled/create_mute_rule/set_notification_route_enabled move reading guidance off tools/list (#3898) #4077, get_pg_logging_audit/get_pg_io_stats/get_pg_wait_sampling move reading guidance off tools/list (#3898) #4081, get_analysis_findings/get_analysis_facts move reading guidance off tools/list (#3898) #4083 and get_deadlocks/get_blocked_process_reports move reading guidance off tools/list (#3898) #4123 said that no guidance was deleted. Each PR removed issue numbers from tool text, and the entries now say so.
• get_pg_io_trend/get_pg_database_trend/get_pg_cpu_utilization move reading guidance off tools/list (#3898) #4092 got wrong what the old get_pg_cpu_utilization text said about Aurora and RDS. It also read as if the tool's behavior changed. Only the description changed, and the entry now says that.
• Darling MCP: a /core endpoint serves the tools analysis points to (#3898 D7) #4121 now mentions the short note at the top of a /core session's instructions.
• Add exact module filtering to Query Store MCP results #4057 had no entry. It now has one under Added, with credit to @kendra-little.

One checker changed a size in #4085 from 614 to 605. That was wrong. #4085's merge commit (83d21a4) sets get_query_duration_trend to 614 in both budget files, so the entry keeps 614.

Merged PRs with no entry

• Store upgrade keeps pg-runtime-prev in place instead of deleting and recreating it (prep for #4052) #4097, Add csvlog record parser for #4053 part a1 (parser only, no wiring) #4104 and Add jsonlog server-log parser (#4053 part a2) #4112 are internal. Their PR bodies say no behavior changed.
• 4053 review round 2: caller-stated csvlog edges + narrower log-format cache invalidation #4140 fixes the csvlog parser and the log-format cache. Both are new since 3.8.0, so no release had the bug. 4053 part b1: pg_deadlocks reads csvlog when it's on #4136 has the csvlog entry.
• McpToolsListBudgetTests: lazy Measure() + service-leak diagnostic on unpinned params (#4075) #4094 and test(darling): live HTTP proof of the web host's gates (#4128a) #4132 change only tests.
• Lane orders: size lanes and finish phases from measured lane cost #4098, lane-orders: size #3898 lanes at one twin pair, check effort, cut long grep lines #4102 and lane-orders: grep saved test logs, never invent an unfilled placeholder #4129 change agent instructions, not the product.

Held back

• 4053 c1: RDS/Aurora pg_log_events reads the csvlog file when csvlog is on #4135 is still open. Its entry stays in the buffer for the next splice.

PR tender verification

• 4053 part b2: pg_plan_capture reads csvlog when it's on (self-hosted) #4137 was missing. It merged at 05:57Z, before this branch was cut, and its body has a ## CHANGELOG entry
  section. It was neither spliced nor listed under "Merged PRs with no entry". Commit 5a676a25 adds its entry
  under Fixed, right after 4053 part b1: pg_deadlocks reads csvlog when it's on #4136's, plus its link. 4053 part b1: pg_deadlocks reads csvlog when it's on #4136's last sentence said plan capture is unchanged, which
  read as a contradiction next to 4053 part b2: pg_plan_capture reads csvlog when it's on (self-hosted) #4137. It now says 4053 part b2: pg_plan_capture reads csvlog when it's on (self-hosted) #4137 covers plan capture.
• Every PR merged to dev since CHANGELOG: the 3.9 wave's 42 entries in one splice, and #3989's entries back in their sections #4080 is now either spliced or listed above. The tender compared the full list
  of 57 merged PRs against both.
• All 49 cited PRs are merged. 4053 c1: RDS/Aurora pg_log_events reads the csvlog file when csvlog is on #4135, still open, is not cited.
• Each entry has exactly one link, and each link has exactly one entry. Add exact module filtering to Query Store MCP results #4057 cites itself as
  ([#4057], contributed by @kendra-little). Every link points at its own PR's URL.
• Every new entry sits under ## [Unreleased]: 3 under Added, 35 under Changed, 11 under Fixed.
• The file keeps CRLF line endings throughout. Against dev, the change is 98 lines added and 0 removed.

Test plan

• The splice script's check: all 3,699 existing lines kept, none moved or removed, and 96 lines added (48 entries and 48 links). With 4053 part b2: pg_plan_capture reads csvlog when it's on (self-hosted) #4137's entry and link, 98 lines are added.
• CI runs its usual checks.

🤖 Generated with Claude Code

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