CPD: remove the duplicated sensor record and response code, gate cpd-check (#115)

[bertysentry]

Closes #115.

Duplicated code (first commit)

CPD reported 9 duplicated blocks (490 lines at 100 tokens), almost all of them the three sensor records copying each other.

• AbstractSensorRecord (new) holds what FullSensorRecord, CompactSensorRecord and EventOnlyRecord share: sensor owner, entity, sensor type, event/reading type, direction, ID string, capabilities and units, record sharing. It decodes them; each subclass only gives its byte offsets, and FullSensorRecord keeps its linearization and thresholds. The three classes go from 1,356 lines to 478, plus 502 in the base class (mostly accessor Javadoc, which the copies lacked).
• IpmiCommandCoder.validateResponse() (new, protected) replaces the response checks copied in 16 commands (DeactivatePayload keeps its own, it tolerates a specific completion code). This fixes three copy-pasted error messages that named the wrong command: ReadFruData said "Get SDR Repository Info", SetSessionPrivilegeLevel said "Get SEL Entry", ChassisControl said "Get Chassis Status". The message now names the command class.
• Sensor and GetSensorsRunner read the shared fields through the base class instead of branching on Full and Compact.
• cpd-check runs at verify for duplications of 100 tokens or more.

Notes for review:

• Threshold: the issue mentions minimumTokens=50, but its list of 9 blocks matches the 100-token default. At 50 tokens, 35 smaller duplications remain (611 lines, mostly the session state machine and the SEL/SDR command coders), outside this issue's scope. The gate is at 100 and the site report still lists 50+.
• API trade-off: to avoid a third class in the hierarchy, FullSensorRecord now also exposes the record-sharing getters (share count 0, no instance modifier) and EventOnlyRecord the unit getters (null); the Javadoc says so. All existing getters and setters keep their signatures.
• The FullSensorRecord formula bugs (accuracy exponent, linearization order, tolerance) are untouched, they belong to FullSensorRecord decoding: thresholds gated on the wrong byte, incomplete linearization, precedence bug in accuracy exponent, tolerance #83.

License headers (second commit)

mvn license:update-file-header, which AGENTS.md asks to run for every new file, rewrote the copyright line of all 278 source files. The parent POM sets canUpdateCopyright (every "Copyright 2023 Verax Systems, MetricsHub" became "Copyright 2023 - 2026 MetricsHub") and canUpdateDescription (on Windows the CRLF system line separator makes every header look outdated, and it gets re-rendered as "Copyright (C) ..."). Both are now false: the plugin adds headers to new files and leaves existing ones alone. The same parent settings probably affect the other projects built on oss-parent.

README and AGENTS.md now state the copyright convention (Verax Systems stays the copyright holder of the files derived from its code) and that the Verax library, published under the GPL v3, is used under the commercial non-GPL license granted to Sentry Software in 2021.

Testing

• mvn verify (JDK 17): 33 tests pass, 0 Checkstyle, PMD and CPD clean. mvn site builds; SpotBugs reports nothing new in the changed files.
• New SensorRecordTest cases decode a Full, a Compact and an Event-Only record field by field. They were written and passed against the previous code before the refactoring. New IpmiCommandCoderTest covers a successful response, an error completion code and a response to another command.
• Live, with the same harness built from main and from this branch:
  • Lenovo IMM (13 Compact and 36 Full records): identical chassis status, FRUs, sensor names, states and thresholds; only live readings (power, fan speed, voltages) differ between runs.
  • GIGABYTE BMC (85 records, incl. 19 OEM D0h): identical output. Both builds occasionally timed out during the FRU read when the BMC drops a reply (300 s per-message timeout, A single lost UDP response stalls collection for 300 s; per-message timeout is not configurable from IpmiClientConfiguration #77); re-runs passed.
• License plugin: update-file-header on the whole tree leaves the 279 existing headers untouched and adds a MetricsHub header to a new file.

🤖 Generated with Claude Code

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Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-07T21:31:27.752643Z	bd464d3	New commits

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