fix(bnf,schema): align idShort with Metamodel Constraint AASd-002

[aorzelskiGH]

Summary

Aligns the idShort grammar and regex used by this spec with the
normative definition in IDTA-01001 Constraint AASd-002:

idShort shall consist of at least two characters and shall only
feature letters, digits, hyphen (-) and underscore (_); starting
mandatory with a letter, and not ending with a hyphen, i.e.
^[a-zA-Z][a-zA-Z0-9_-]*[a-zA-Z0-9_]+$.

Problem

Both the BNF and the JSON Schema / OpenAPI regex marked the trailing
character group optional:

• BNF (<idShort>):
  ( L (( L | D | "_" | "-" )* ( L | D | "_" ))? )
• Regex:
  [A-Za-z](?:[A-Za-z0-9_-]*[A-Za-z0-9_])?

That allowed single-character idShorts (e.g. A) and, through the
* + optional group, idShorts whose trailing character group was
simply absent — both of which AASd-002 forbids.

Solution

Make the trailing character group mandatory so there is always at
least one "non-hyphen" character after the initial letter:

• BNF:
  ( L ( L | D | "_" | "-" )* ( L | D | "_" ) )
• Regex:
  [A-Za-z][A-Za-z0-9_-]*[A-Za-z0-9_]

Equivalent to AASd-002. Minimum length is now 2; a trailing hyphen
is disallowed.

Files touched (per repo):

• aas-specs-api:
  • documentation/IDTA-01002-3/modules/ROOT/partials/bnf/grammar.bnf
  • documentation/IDTA-01002-3/modules/ROOT/partials/query-json-schema.json
  • documentation/IDTA-01002-3/modules/ROOT/pages/schema.adoc
  • Part2-API-Schemas/openapi.yaml
• aas-specs-security:
  • documentation/IDTA-01004/modules/ROOT/partials/bnf/access-rules.bnf
  • documentation/IDTA-01004/modules/ROOT/partials/json/aas-queries-and-access-rules-schema.json
  • documentation/IDTA-01004/modules/ROOT/partials/json/formulas-and-logical-expressions.json

Impact

• Affected specs: IDTA-01002 and IDTA-01004.
• Strictly tightens the accepted set of idShorts; any idShort that is
  valid under AASd-002 remains valid here.
• Single-letter idShorts and trailing-hyphen idShorts — which were
  always disallowed by AASd-002 but accepted by this spec — are now
  rejected, matching the Metamodel spec.
• No runtime behaviour change for conforming AAS content.

Review notes

• Please confirm no examples in the repo rely on single-letter or
  trailing-hyphen idShorts. A quick scan of partials/examples/
  found none.
• Paired PR in the sister repo carries the identical BNF/regex
  change; both should land together.

Related

Review Finding T-06: idShort regex inconsistent with AASd-002.