RFR: 6004: Should add tenuring summary to the GC visualization [v2]

[Aymane Harmaz]

> This change adds a new tab to display the tenuring distribution for GC cycles.
> 
> There are 3 case scenarios:
> - Single GC cycle selected: A histogram chart is shown representing the tenuring distribution (total size across ages) for the selected cycle.
> - No GC cycle selected: An informational message is displayed to prompt the user to select a cycle.
> - Multiple GC cycles selected: An informational message is displayed indicating that only a single cycle can be viewed at a time.
> This enhancement improves visibility into object tenuring during individual GC cycles. 
> 
> <img width="1174" height="599" alt="Screenshot 2025-10-15 at 16 51 19" src="https://github.com/user-attachments/assets/76ce69c2-60eb-48c8-be9f-6387cbfa7c42" />
> 
> <img width="1174" height="599" alt="Screenshot 2025-10-15 at 16 51 34" src="https://github.com/user-attachments/assets/a5fc9bc9-fa72-42c9-aeb2-ecad21e4ac66" />
> 
> <img width="1174" height="599" alt="Screenshot 2025-10-15 at 16 51 57" src="https://github.com/user-attachments/assets/63ffba47-8e08-430a-9a28-11473b59e6dc" />

Aymane Harmaz has updated the pull request incrementally with one additional commit since the last revision:

  Implemented review comments

-------------

Changes:
  - all: https://git.openjdk.org/jmc/pull/679/files
  - new: https://git.openjdk.org/jmc/pull/679/files/fc0c4c26..18eeb4af

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jmc&pr=679&range=01
 - incr: https://webrevs.openjdk.org/?repo=jmc&pr=679&range=00-01

  Stats: 30 lines in 4 files changed: 14 ins; 1 del; 15 mod
  Patch: https://git.openjdk.org/jmc/pull/679.diff
  Fetch: git fetch https://git.openjdk.org/jmc.git pull/679/head:pull/679

PR: https://git.openjdk.org/jmc/pull/679