Fleet UI: Handle long fleet names across the Fleets UI

[RachelElysia]

Issue

Closes #47290

Also implements the "Cap free-text maxLength to the backend column length" pattern established in #49041 (patterns.md thread).

Description

Fleet name inputs had no maxLength cap and no service-layer length check, so a name >255 chars failed with a raw MySQL Data too long error, and several UI surfaces didn't handle long names gracefully. This PR fixes all four manifestations called out in the bug, plus a related label-overflow case on the host details page, and hardens adjacent name inputs across the app.

Frontend fixes for #47290:

• Create/Rename fleet name inputs now cap at 255 characters (matches teams.name varchar(255)).
• Fleets table Name column uses LinkCell with tooltipTruncate + className="w400" so long names truncate with an ellipsis and full-name tooltip instead of overflowing across the Hosts/Users columns.
• Fleet-detail page header (.team-details__team-header): h1 gets overflow: hidden; text-overflow: ellipsis; white-space: nowrap;, __team-details gets min-width: 0; flex: 1, and .action-buttons gets flex-shrink: 0 + white-space: nowrap on buttons so Manage enroll secrets / Rename / Delete no longer wrap to a second line when the fleet name is long.
• Manage enroll secrets modal body — __description gets overflow-wrap: anywhere; min-width: 0 so a long <b>{fleet name}</b> wraps within the modal instead of spilling out the right edge.
• TeamsDropdown (used as the fleet-detail header selector for multi-team users, and in other headers): wrapper is shrinkable; the react-select control, single-value, and option styles get ellipsis-truncation; menu is capped at maxWidth: 500px so long team names in the option list don't blow out the menu.

Backend fixes for #47290:

• New fleet.MaxTeamNameLength = 255 constant.
• NewTeam, ModifyTeam, and ApplyTeamSpecs now return fleet.NewInvalidArgumentError("name", "may not exceed 255 characters") instead of surfacing a raw Data too long MySQL error. Covers UI, API, and GitOps entry points.

Broader consistency pass (per #49041 thread):

• New shared MAX_ENTITY_NAME_LENGTH = 255 constant in frontend/utilities/constants.tsx.
• Refactored 8 existing files that had ad-hoc NAME_MAX_LENGTH = 255 / MAX_LABEL_NAME_LENGTH = 255 locals to use it.
• Slotted it into 16 additional InputField name/description inputs that were missing a cap (API user, custom variable, certificate, label name + description, pack name + description, and all 5 CA forms — CustomEST, CustomSCEP, Smallstep, Digicert, Hydrant).
• Pruned dead FE length validators that can no longer fire now that the DOM cap enforces the limit (certificate modal, custom variable modal, both label helpers, both category modals). Unusual/shorter caps (e.g. varchar(64), custom business rules) still keep their inline validators — silent truncation is only appropriate for the common 255-char norm.

Bonus: fixed the long-label overflow on the host details Labels card by capping the pill button max-width at 300px.

Screenrecording

Testing

• Added/updated automated tests
• QA'd all new/changed functionality manually

Test coverage:

• CreateFleetModal.tests.tsx, RenameFleetModal.tests.tsx — new case per file asserting the name input's maxLength === 255.
• AddCertificateModal.tests.tsx, Variables.tests.tsx — the existing "shows too-long error when pasting 256 chars" tests are now unreachable via the DOM cap; converted to maxLength === 255 assertions.
• ee/server/service/teams_test.go — TestNewTeamNameValidation, TestModifyTeamNameValidation, and TestApplyTeamSpecsNameValidation each get two new cases (accepts at the limit, rejects one over with the expected error message).

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 67.99%. Comparing base (fb3932f) to head (3ce51d8).
⚠️ Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #49216      +/-   ##
==========================================
- Coverage   67.99%   67.99%   -0.01%     
==========================================
  Files        3779     3779              
  Lines      239083   239089       +6     
  Branches    12463    12607     +144     
==========================================
+ Hits       162564   162568       +4     
- Misses      61756    61757       +1     
- Partials    14763    14764       +1     

Flag	Coverage Δ
backend	69.56% <100.00%> (+<0.01%)	⬆️
frontend	59.34% <100.00%> (-0.02%)	⬇️

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[RachelElysia]

@claude review